Reenforced abrasive member and method of making the same



June 1, 1937. A. w. COFFMAN REENFORCED ABRASIVE MEMBER AND METHOD OF MAKING THE SAME Filed June 11, 1955 Patented June 1, 1937 rArsNr orrlce REENFORCED ABRASWE DIEIVEEB METHOD OF MAKING Tm SAM Alden W.- Cofiman, Pittsburgh, Pa, assignor to H. H. Robertson Company, Pittsburgh, Pa a "corporation of Pennsylvania Application June 11, 1935, Serial No. 26,07? 6 Claims. (oi. 51 -209) This invention relates to a novel reentorced abrasive member and to a process for making the same.

The abrasive member may be of different forms, to-enable it to be used for different purposes as for instance, it may be circular in form and used as a grinding wheel or it may be of a substantially fiat form and used as a nonslipping head. 'The reenforcing member may be made of metal, preferably steel.

The abrasive member is provided with a porous surface to which the reenforcing member is applied and firmly secured thereto by a metal adhesive which not only bonds the reenforcing memher to the abrasive member but also mechanically attaches them to each other as will be described.

The reenforced abrasive member may and prefersbly will be produced by providing the porous a surface of the abrasive member with a layer or 53 coating of a metal or alloy of relatively low melting point, and providing the steel or other metal reenforcing member with a layer or coating of metal or alloy of relatively low melting point, then assembling the reenforcing and abrasive members with their coated surfaces together, and subjecting them to heat and pressure to unite the coating metals of relatively lowmeltlng point and form a metallic adhesive which not only bonds the reeniorcing member to the abrasive member but also mechanically connects them to,

each other.

These and other features of the invention will be pointed out in the claims at the end oi this specification.

In the drawing illustrating the preferred embodiment of the invention, Fig. 1 illustrates an elevation of a reenforced grinding wheel embodying the invention; Fig. 2 is a similar view of a m modified form of the reenforced grinding wheel;

Fig. 3 is a similar view of an abrasive block suitable for use as a stair tread and which embodies the invention; and Hg. 4.- is an enlarged detail illustrating the bonding of metal adhesive to the abrasive member and to the metal reenforcing member.

In the manufacture of abrasive members it is desirable to reeniorce the abrasive member by a metal member. The strength of the, abrasive member is substantially increased by the reenforclng member, and the frlabillty of the abrasive member is substantially decreased. In addition the metal member forms a convenient member for securing or attaching the abrasive member to its 5 support whether the abrasive member be a grindin: wheel or in block form, such tor example as a stairtread. Accordingly, the present invention contemplates the production of a novel and improved reenforced abrasive member in which the metal reenforcing member is secured or attached to the abrasive member by an interposed 5 metal adhesive which is alloyed to the metal member and is keyed to the abrasive member.

Referring now to the drawing which illustrates the preferred embodiments of the invention, ill represents an abrasive member which in Figs. 1 and 2 has been illustrated as a conventional form of grinding wheel of carboruridum or alloxite, or other material. Such abrasive members are characterized by a substantial porosity of surface, and in accordance with the present invention the grinding member it is secured to a metal reen forcing member i2 by an interposed body it of metal adhesive. The reenforcing member it preferably comprises steel or other metals such as copper, brass, bronze, and the like, which are 2% capable of alloying with a metal adhesive. The metaladhesive may comprise a'metal or alloy selected from the group comprising zinc, cadmium, tin, lead, and alloys thereof, and any other alloys which are capable of alloying with. the metal member, it being understood that a metal adhesive will be used which is capable of alloying with the particular metal reeniorcing member employed. As best illustrated in Fig. i, the metal adhesive is alloyed to the metal reeniorc- 3% ing member and keyed to the particles it making up the surface of the abrasive member, thereby providing an extremely strong bond between the reenforclng member and the abrasive member.

In producing the present improved reenforced abrasive member, I prefer to apply a metal adhesive oi the character specified to the surf-ace of the metal reenforcing member, in accordance with any usual or preferred process, such for ereample as by dipping the reenforcing member in 49 a molten bath of the metal adhesive. I also prefer to apply the metal adhesive to the surface of the abrasive member upon which the reenforcing member is to be attached, and this may conveniently be done by spraying the metal adhesive in a molten condition onto thesurface of the abrasive member, thereby causing the particles of the molten metal adhesive to enter into the pores or openings between the particles upon the surface-of the abrasive member and providing a, so layer or coating of the metal adhesive upon the surface thereof. After these operations have been corripletedpthen the abraslve'member and reenforcing member are assembled with the metal adhesive coatings and contact and subjected to F heat and pressure to alloy the two metal adhesive layers and form a unitary bonding layer.

As a modification of the preferred process, if found advantageous the metal adhesive may be applied by a spraying operation upon the surface of the abrasive member and then a coating of metal adhesive may be applied to the metal reenforcing member and before cooling of the metal adhesive upon the metal reenforcing member, the reenforcing member and abrasive member may be united under pressure to eflect the alloying of ,the two metal adhesive layers together.

Another modification of the preferred process comprises the application of the metal adhesive layer to the metal reenforcing member in sufficient amount as to enable a single layer of metal adhesive to be utilized so that by assembling the metal reenforcing member and the abrasive member and maintaining the metal adhesive in a molten or fluid condition, it is possible to eflect the desired keying action between the metal adhesive and the surface of the abrasive member. In order to assist the keying operation, it is preferred to subject the abrasive member to vacuum or suction to help or assist the penetration of the molten adhesive into the carried on as above.

pores of the abrasive member.

While any of the above-mentioned metal adhesives may be sprayed or otherwise applied directly to the surface of the abrasive member, in some instances it may be preferred to prime the surface of the abrasive member with a metal such as copper having a higher melting point and greater strength than the metal adhesives above referred to, and this may be. done by spraying the molten copper or other metal into the pores on the surface of the abrasive member, and thereafter the process of securing or attaching the metal reenforcing member may be In such case it is preferred, although it is not absolutely necessary, to utilize a flux as a solution of zinc chloride or other known flux in order to assist in the alloying of the remaining metal adhesive to the copper.

In the application of the pressure during the bonding operation it is desirable that the metal reenforcing member and the abrasive member be subjected to uniformly distributed pressure in order that the bonding operation may take place over the entire contacting surfaces or parts. The amount of pressure may vary within a rather wide range, but it is preferred to operate utilizing relatively low pressures on account of the friable nature of commercial abrasive members.

As illustrated in the drawing, the metal reenforcing member may be secured to the rear face of the grinding wheel, particularly when such wheel is to be used for surface grinding.

panding the collar in any convenient manner,

I may readily secure the desired pressure to effect the keying of the metal adhesive into the pores of the grinding wheel. The collar may and preferably will be provided with a suitable keyway 22 in order to permit the collar and grinding wheel to be keyed to the usual shaft upon which the wheel may be mounted in use.

From the description thus far it will be observed that the improved abrasive member, particularly when in the form of a grinding wheel. possesses increased strength. The grinding member embodying the presentinvention may be worn down to within a very short distance of a metal adhesive layer, and as a result these grinding members possess greater life than grinding members of the prior art.

While the preferred embodiments of the invention have been described what is claimed is:--

1. The method of producing a reenforced abrasive member having a porous surface, which consists in applying to the porous surface of the abrasive member a metal coating of relatively low melting point, applying to the reenforcing member a metal coating of relatively low melting point, assembling the reenforcing member and the abrasive member with their coated surfaces together, and subjecting the assembled members to heat and pressure.

2. As a new article of manufacture, an abrasive member provided with pores throughout, a metal backing member of substantial thickness .and strength, a relatively thin layer of metallic to said backing member whereby said abrasive member is rigidly secured to said backing member solely by said interposed layer of metallic adhesive and which constitutes a metallic bond, the porous nature of the abrasive member permitting the same to be ground down substantially to the metal bond provided by the metal adhesive.

3. The method of producing a reenforcing abrasive member by uniting a metallic reenforcing element with an abrasive element, by an interposed layer of metallic adhesive, the steps which comprise applying a metal coating'to one of said elements, and while said coating is still in an adhesive condition applying the other of said elements thereto, under pressure, whereby said interposed layer of metallic adhesive is bonded to said members respectively to rigidly secure the same together.

4. The method of producing a reenforcing abrasive member by uniting a metallic reenforcing element with an abrasive element by an interposed layer of metallic adhesive, the steps which' the reenforcing member to the abrasive member,

while the metal coating is still in adhesive condition, and subjecting the assembled members to pressure whereby to firmly secure the abrasive member to said reenforcing member.

5. The method of producing a reenforcing abrasive member having a porous surface which comprises the steps of applying, by spraying, to the porous surface of the abrasive member a metal coating, app l to the reenforcing member a metal coating, assembling the reenforcing member and the abrasive member with their coated surfaces together whereby to securely fix the abrasive member to the reenforcing member.

6. As a new article of manufacture..an abrasive member provided with a non-metallic binder and being porous throughout, a metal backing member of substantial thickness and strength,

to the 'backin'g'member solely by the interposed layer 01' metallicadhesive which constitutes a metallic bond, the porous nature of the abrasive member permitting the same to be ground down substantially to its point of bond.

ALDEN w. cor'rmrt. 

